regular xpression stuff

[Anonymous Monk]

what is a regular expression to match a word containging all and only a set of characters? egs: for the set t,a,b tab should match and bat should match but not bbat or brat!

[Masem]

In this case, you don't want a regex, at least directly. I think we've golfed this once, but in general:

my $to_be_matched = 'tab';
my $word = 'bat';
if ( join '', sort split(//, $word) eq 
     join '', sort split(//, $to_be_matched ) ) {
   # Success!
} else {
   # Failure
}

Update - $ instead of @ on to_be_matched

-----------------------------------------------------
Dr. Michael K. Neylon - [e-mail] || "You've left the lens cap of your mind on again, Pinky" - The Brain
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[screamingeagle]

shouldnt

 
if ( join '', sort split(//, $word) eq 
     join '', sort split(//, $to_be_matched ) ) {

be

if ( join('', sort split(//, $word)) eq join('', sort split(//, $to_be
+_matched)) ) {

(extra parenthesis added )

After adding the parenthesis , i get "Success" (i.e. "bat" = "tab" based on your example), without them the result is "Failure"

[Parham]

this would also work

$var = 'bat';
if ($var =~ /^[bat]{3}$/) { print "match"; } else { print "fail"; }

since you want only those letters to exist, check from beginning to end that word for each letter, the {3} should be the number of letters in that word

[count0]

If I'm understanding the question correctly, this will not work.

It seems that the inquiring monk wants to match each letter once and only once.
/^[bat]{3}$/ could match 'ttt', 'bba', 'aaa', etc. If that *is* undesirable, Masem's excellent reply is probably the best way to go.

[Parham]

count0++ i forgot to take that into consideration

[Lucky]

Looks terrific but works:

@to_check=('bat','bbat','brat');
for (@to_check){
 if (/^([bat])(?!\1)([bat])(?!\2)([bat])(?!\3)/){
   # do something
 }
}

Just create regexp dynamically.

[gt8073a]

if (/^([bat])(?!\1)([bat])(?!\2)([bat])(?!\3)/){</i>

This does not entirely work, 'bab', for instance, passes the match.

the following modified version works, but it is not too elegant, just imagine checking a 5 letter word!

if (/^([bat])(?!\1)([bat])(?!\2|\1)([bat])(?!\3|\2|\1)/){

Will perl for money
JJ Knitis
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[Lucky]

For any word:

my $set='bat';
my $regexp;
for (my $i=1;$i<=length($set);$i++){
 my $x=join '|', map {"\\$_"} 1..$i;
 $regexp.="([$set])(?!$x)";
}
if (/^$regexp/){
  # do something
}

Terrible... :-)